Aircraft such as commercial airliners typically include a variety of ducts for routing fluids such as air throughout the aircraft. For example, a commercial aircraft may include multiple ducts for routing conditioned air throughout the aircraft cabin as part of the aircraft environmental control system. Because of the need to provide the conditioned air at a controlled temperature, environmental control system ducts may be insulated.
Current methods for manufacturing ducts for an aircraft include the use of casting molds. Fiberglass may be laid up over one or more casting molds. After the fiberglass cures, foam may be separately bonded to the fiberglass to provide insulative capability for the duct. Unfortunately, the process of manufacturing casting molds is labor intensive. In addition, the use of casting molds generates large amounts of scrap material and/or waste material which increases the overall cost of the duct.
In another method, a plaster mandrel may be employed for laying up composite material or plies over the plaster mandrel. After the composite plies are cured, the plaster mandrel may be destroyed during the process of separating the duct from the mandrel which results in a large amount of waste material. In addition, the process of laying up composite plies on the plaster mandrel is time-consuming and labor intensive. Furthermore, for thermosetting composite materials, the thermosetting material must be stored at a relatively cold temperature until ready for use. The cost of storing (e.g., refrigerating) the thermosetting composite materials adds to the cost of the duct.
As can be seen, there exists a need in the art for a method of forming a duct such as for an environmental control system of an aircraft and wherein the duct can be produced without the generation of large amounts of scrap or waste material. Furthermore, there exists a need in the art for a method of forming a duct that requires a minimal amount of labor and which can be produced in a relatively short period of time. In addition, there exists a need in the art for a relatively simple method of forming a lightweight duct that can be fabricated at relatively low cost.